A Turkish high court has suspended an attempt by the government to funnel all corruption investigations through top police and judicial officials.

Critics have accused Prime Minister Recep Tayyip Erdogan of trying to stifle a corruption investigation targeting some of his allies and members of their families by dismissing police chiefs and changing the rules on how the probe is being conducted.

Three ministers had earlier resigned after their sons were among dozens detained on December 17 as part of the probe into corrupt procurement practices.

Mr Erdogan responded to widespread criticism of high-handed attitudes in his government by replacing half of his cabinet with loyalists on Wednesday.

He claimed that the probe was part of a wider conspiracy aimed at bringing his government down.

But the high administrative court said yesterday that it was suspending the government's change to corruption case regulations pending more deliberation.

Prosecutor Muammer Akkas had claimed that he had been removed from the case, which he described as compromised by police who had refused to comply with orders to arrest more suspects.

"By means of the police force the judiciary was subjected to open pressure and the execution of court orders was obstructed," Mr Akkas alleged.

"Suspects have been allowed to take precautions, flee and tamper with the evidence."

However, Turkish chief prosecutor Turhan Colakkadi claimed that Mr Akkas had been removed from the case for leaking information to the media and refusing to acquaint his superiors with details of the investigation.